This invention relates to a system and a method for providing a security check on a record medium or credit card used in security of financial systems and the like, and to a novel record medium or credit card construction used therein and its associated method of manufacturing.
Recent developments in security or financial systems, credit systems, funds transfer systems, and the like, rely heavily on the use of record media or credit cards having magnetic stripes or tracks thereon with various data such as account number, credit limits, credit status, credit available for use, and the like, being recorded magnetically on the stripes. Such systems have to be designed to avoid or minimize the fraudulent use of such record media or credit cards.
One of the ways in which fraudulent use of such credit cards is made is to counterfeit the cards by mass reproduction techniques which "skim" or transfer the data magnetically recorded on a valid card to a fraudulent one.
The problem of trying to prevent the unauthorized duplication of or use of valid credit cards used in financial, credit or security systems, and the like, is a very extensive one as evidenced by the variety of different techniques tried to avoid the problem and disclosed in the following U.S. Pat. Nos.: 3,604,901; 3,759,179; 3,620,590; 3,790,754; 3,644,716; 3,808,404, and 3,831,008. None of these prior art patents shows the approach used in this invention to prevent the unauthorized duplication or use of valid credit cards. U.S. Pat. No. 3,620,590 for example shows the use of a credit card having a scrambled holographic image and a secret number containing the signature of the bearer, therein, and a special apparatus for unscrambling the image to display the signature and number when the card is used to make a purchase.
Some prior art techniques for providing a security system for checking on the validity of a credit card used in the system are shown in the following U.S. Pat. No. which are merely typical of the prior art: U.S. Pat. Nos. 3,401,830; 3,691,527, and 3,513,298; 3,697,729. None of these patents discloses a system which uses diffraction gratings on a credit card in conjunction with a second form of data like a magnetic track to provide a security check on the credit card being used in the system.
Some systems for recording digital information using diffraction gratings are shown in the following U.S. Pat. Nos.: 3,312,955; 3,599,147; 3,392,400; 3,635,545; 3,523,734; 3,656,838, and 3,838,401. While these patents show the use of diffraction gratings in systems for recording information, the systems employ structure which is quite different from that employed in this invention, i.e. several patents disclose grating plates and slotted masks to record data on a photographic film, or circular rotating mirrors in combination with grating plates for character identification.